I've owned the digiZoid ZO for just a little while now, but it has really grown on me! It's the perfect amp for bassheads. It's pretty much an external EQ for your music player. It was absolutely fantastic using this listening to dubstep. The build quality isn't the best, mainly a bunch of cheap plastic but it's fairly lightweight so I'm comfortable throwing it around. It's really straight-forward as it only has one button which is used to increase/decrease the bass and power on/off. I'm not a huge fan of the colours as a measurement because it's not as easy to maneuver, "What's your favorite setting?" "Oh, I really like kinda orange-red". Also YOU CAN'T USE LODs. There is no volume control on this amp so you can't use an LOD for an iPod or anything with it. There is a fairly present hiss when there is no music playing, but you can't really hear it once the music starts. That SmartVektor voodoo-believe it or not- WORKS. Yeah, that's right, it works. It gives your music a more full sound, I've also noticed it cleans up a bit of the distortion.

Overall, perfect for bassheads, good if you can find it for a cheaper price, makes your music sound better. I think it's a good buy!

Cons: Constant buzzing heard when charging while listening, via USB. Thus it's better to let it charge overnight, and enjoy the Zo unplugged from the USB.

I can't even begin to say how well the Zo works; just as advertised, no ifs and buts! To keep things short and simple, if you want powerful, thumping, top-notch quality bass gain, you need not look anywhere else, ever, again! When it comes to amps, I'm a skeptic, to say the least. While many offer potential 'tweaks', which (to a lesser extent) can be acquired through careful EQ-ing, the tweaks are hardly ever worth the premium paid IMO. The Zo on the other hand is priced competitively, and is in turn the absolute best bang for the buck. Monsterous sub-bass gain, with no noticeable midrange bleed whatsoever; coupled with a warm presentation that pushes the entire signature slightly forward and in your face (else the bass would seem too overpowering, were it not for the treble and mids pushed slightly forward). Seriously, stop reading this, and pick one up. You'll never revert to listening without it again!

I would like to say my deepest gratitude to bro sherwino for hitching me in his group buy...without him i could never get my hands on this beautiful thing - the ZO.

this is the story of the ZO...

what is the ZO?
well, to me, its like a boost.
a boost not only in volume but in frequency, in bass, and unheard details/details that are buried in your music.
its a small device that uplifts the experience and bring you to another league of FUN.

I strongly believed that this item is not just an amp.

well, from there ill try to define it more in experience.
i tried using my iems with it.
and the grado sr325is can.
and i really liked how it performed...and what it did to my music.
its really worth every penny to me.

IMPORTANT:
i would like to clarify things here...
it cannot be use in your LINE OUT directly.
it will give you UNBEARABLE amount of volume...specially if youre using low impendance iems.
its not yet meant to be use directly to your dap's line out.
if you want to use the LINE OUT and your ZO, you'll have to use amp between them to control the amount of volume that would go to your gear (iem or hp).

you can charge this item thru any USB port.
so charging is easy and hassle free...
a blue light to indicate that your unit is in charge mode.

there is a LIGHT SCALE that serves as an indicator to the level of bass that youre in.
green for minimum and red for max level.

INPUT and OUTPUT jacks.
and one button at the side to control the level of bass and to turn the unit ON and OFF.

WELL, enough of too much basic features...what about the sound?

i would highly recommend the ZO to all BA iem users.
wether you are using a CUSTOM or UNIVERSAL BA iems.
its a great pair with your gear.

UE700
been using this with my UE700.
ZO level to the max.
and i got a beautiful BA bass.
the only bass i have experienced before in a BA is the SM3 and the ortofon eq7.
and it beats them.
its a lot leaner and stronger...
more mature and slower-slow bass that longed in the air, ala-DYNAMIC but still a BA.
with both quality and a bit of quantity.
it became better.
it increases mid bass...something like a fun kind of bass with thicker presentation.
call it fullness, there is that with a ZO.

MX980
this is an earbud with a very smooth high, clinical in presentation, very musical.
pair it with a ZO, and this earbud became tamed....no sharpness of highs, with warmish mids and leaner bass...again.
i like it!!!
ZO level to the max.

FX700
now this is already almost perfect iem for me...
and i like how it really sound.
im selling my grado sr325is because of this.
i think i already found the period to the end of the sentence...to this journey.
and to me, its the fx700.

well, my impression is a bit mixed...
see, im using ZO level always to the max, with my ue700 and the mx980.
and here, i cant. i just cant justify to add more brute force of bass to my herculean fx700.

i can only use level 1 to 8 with it.
add more and it becomes more unrealistic...the bass would became ridiculously MONSTROUS.
im no basshead, and i only enjoy a good amount of bass.
too much will be fatiguing to me in the long run...it would be a fun ride..you know..
and we all know anything with TOO MUCH is bad.

so...i cant go ZO level to the max with my precious dynamic.

what it did to my fx700 is a warmish and fuller mids.
more greater details and nuances.

really?
YES.
i gave you my word.
tried listening to ITS MY TURN by DIANA ROSS.
turn the ZO off and you wont hear a detailed part very clearly to your dap's HP Out.
turn ON the ZO and youll be amazed how that detail was absent in your dap's hp out...almost barely audible in your dap. but with ZO, its clear as a day, its there!

see?
the ZO isnt just an amp.
it would do something more with your music.
with your experience.

the magic begins.
it would make the grado more stronger, leaner and better.
the mids will became fuller.
with tamed highs, just like what it did to my mx980, and the strident highs...its gone.
just all the goodness, all that retains.

i like what the zo did here too.

CONCLUSION:
a ZO is not just an AMP.
i believe.
it does a lot of things.
you can read again in my gears on things that the ZO did.
gears reacts to the ZO differently.
i got very good results with my can and with my BA iem ue700.

what more if its an sm3?
or a tf10, or a um3x?

feel something's missing with it?
maybe the ZO is the answer for sure.
its an extraordinary experience.

i tried the e5 and the e7 of fiio.
and its not like that.
i have a maverick audio d1 with an amp...and the ZO is not just like that.
its not an amp only.

i cannot tell what magic did the digizoid did here...
but im dumbfounded.

its a thing that i cant live without anymore...TRUE.

this thing is dangerous.
youll be attached to this specially when you hear that your gears gets better with ZO.
not only the gears, but also the experience.
YOU and your music.

try to turn it off and youll hear how your hp out sounds... anemic.
turn it on and your music will sound fuller. the mids will became awesome, strident highs will became tamed, and bass, well, that would depend to you, to your liking.

The zo is an interesting product. It seems like it would be just marketing fluff, but it actually does work like they claim. I was able to get (seemingly) hard hitting bass out of some headphones that had never been able to produce anything like that before. As a portable amp, the zo is a bit better than most cheaper amps you would find, such as the various cmoy based designs on ebay. But the real star of this show is the smartvector bass contour EQ feature.

My only issue with it is that the target market is a bit ambiguous. It seems like it would be an entry level product for beginners, but that's decieving.... most really cheap consumer headphones are already too bass heavy so this won't pair well. If you have a decent budget headphone or IEM, it might arguably be better to spend the $100 on an upgraded model rather than the zo. So it ends up being enthusiasts who already have several headphone models who will get the most out of the zo; but those are the same people who are likely the most skeptical of this this type of product. At least digiZoid offers a free trial period.

I'd like to see this technology licensed to some higher end equipment. This could be one of those things like crossfeed that some people would get a lot of use out of.

Unleash the true performance held captive by your audio system and discover the power of sound.
The zo is the world's first "speakerless subwoofer" and electronic audio enhancement device offering an affordable and versatile alternative for improving sound reproduction from any audio system. Whether you are listening with a portable media player and earbuds, an all-out home theater system, or anything in between, zo delivers a remarkably enhanced listening experience beyond your imagination. Additionally, the zo allows you to choose from a variety of enhancement settings, putting you in control of the listening experience. Whether you crave the impact of a 12" subwoofer for rumbling bass, increased vocal audibility, or accentuated clarity, the choice is at your fingertips with zo's user friendly one touch control. The zo is a sleek pocket-sized unit about the size of an iPod nano, weighs less than an ounce, and easily connects-up whenever, wherever, and to whatever you desire. Simply connect the zo between your portable player and sound delivery device using the included cables, and immerse yourself in pure listening pleasure. Besides zo's remarkable listening experience, its built-in rechargeable battery will help to preserve the battery life of your portable player and enable you to watch movies or listen to your music for longer periods of time between recharges. Additionally, zo was designed and is manufactured in the USA.